In a statement Joyce says “a relationship of strong mutual confidence between the Secretary and myself was not a realistic prospect”, adding that Grimes agreed that was the case.

Fairfax Media reports that the pair “have been at loggerheads” since they began working together 18 months ago, but things came to a head recently over changes to Hansard made by staff in Joyce’s office.

ALP agriculture spokesperson Joel Fitzgibbon has been pursuing the minister in Senate estimates over the changes to the parliamentary record.

Joyce said he was unaware of the changes clarifying his comments on drought assistance, but asked for the original Hansard transcript to be reinstated when he found out several days later. He dismissed Fitzgibbon as pursuing a “grand conspiracy”.

Grimes went on stress leave last week after writing to members of Senate estimates saying he had “highly pertinent” information on the matter and wanted the committee to convene an unscheduled hearing. They did and he took most questions on notice.

The former secretary and his minister could not even agree on how to describe the former’s departure. Joyce said in his statement that Grimes “will step down”, but the public servant emailed colleagues on Friday afternoon saying he had been “terminated”.